Inhaltsbereich
GNSS Atmosphere Sounding
Logo of the GNSS Atmosphere Sounding
Ground-based GPS data from a global and from regional networks are analyzed in near-real time. Resulting data products (zenith and slant total delay, integrated water vapor) are provided for the operational assimilation to regional weather models and for several scientific investigations. GFZ also supports temporary atmospheric measuring campaigns (e.g. CSIP: 2006; COPS:2007; WMO-LUAMI:2008 or HYMEX 2012) by the installation, operation and data analysis of GPS ground stations. GPS slant data from the German network (around 400 stations in analysis as of Dec. 2012) are used to reconstruct 3D water vapor distributions.
A second pillar of GFZ expertise in atmospheric sounding is the satellite based GPS radio occultation (RO) technique for precise vertical atmospheric sounding on a global scale. The GFZ spectrum here covers activities related to data processing (CHAMP, GRACE, TerraSAR-X, TanDEM-X, Metop, COSMIC), but also the application of the RO data for various scientific investigations at GFZ. An example for the data processing is the provision of GPS RO data from GRACE-A and TerraSAR-X in near-real time for the continuous assimilation to improve weather forecasts at different national and international weather centers. Scientific investigations focus to the exploitation of the RO data for climatological investigations of tropopause and gravity wave characteristics, but also to detailed analysis of the occurrence of ionospheric irregularities. Additional investigations are related to the design of new satellite missions using GPS remote sensing techniques.
The main part of the GFZ activities in GNSS atmosphere sounding is performed within the Helmholtz Research field "Earth and Environment", programme "Atmosphere and Climate" in close cooperation with KIT and FZ Jülich.
ATMO-CHAMP/GRACE
The research project ATMO-CHAMP/GRACE is funded within the GEOTECHNOLOGIEN programme of BMBF (2009-2011).
GPS radio occultation with CHAMP
The GPS radio occultation data of the German CHAMP satellite are analysed and globally distributed vertical atmospheric profiles (bending angles, refractivity, temperature, water vapor) are derived and provided for the international user community.
Improvement of precipitation forecast with GPS
The research projects COPS-GRID ("High-resolution Reanalyses and Impact Studies for Improving Process Understanding and Precipitation Forecast Skill based on the COPS Data Set") followed by APRO-GRAVAR ("Assimilation and Process Studies for selected COPS IOPs using GPS STD and radar radial velocities in the WRF-Var system") were funded within the DFG priority programme "Quantitative precipitation forecast, SPP 1167).
GPS radio occultation with COSMIC
GPS radio occultation data of the U.S.-Taiwan multi satellite constellation COSMIC/FORMOSAT-3 are used to derive (for selected periods) to derive globally distributed vertical atmospheric profiles (bending angles refractivity, temperature, and water vapor). The data products, provided by UCAR, are used for various scientific applications in atmospheric/ionospheric research..
GPS radio occultation with GRACE
The GPS radio occultation data of the German-U.S. GRACE satellites are analysed and globally distributed vertical atmospheric profiles (bending angles, refractivity, temperature, water vapor) are derived and provided for the international user community.
Gravity wave coupling processes
The research project GW-CODE (Gravity wave coupling processes and their decadal variation) is funded within the DFG priority program CAWSES (Climate and Weather of the Sun-Earth System). Within the project global variations of atmosperic wave phenomena are investigated using, among others, satellite data from CHAMP and GRACE. The project is performed in close cooperation with University Leipzig and Forschungszentrum Jülich.
Atmospheric correction for geoid determination from GRACE data
The research project IDEAL-GRACE is funded within the DFG priority program 1257 "Mass Transports and and Mass Distribution in the Earth system. Within the project the influence of atmospheric data and their errors to determination of GRACE based geoid models is investigated. The project is performed in close cooperation with TU Munich, University Hamburg and DLR.
GNSS Water Vapour Tomography
The GNSS tomography is an attempt to utilize the existing GNSS infrastructure for meteorological applications and to provide temporally and spatially resolved water vapour fields on a national or European scale.
Global atmospheric data from CHAMP and GRACE
Within the research project NRT-RO (Near Real-Time-Radio Occultation) scientific data analysis software for satellite orbit determination and radio occultation processing is developed which is used for the operational data analysis of the GPS based atmospheric data from CHAMP and GRACE.
The resulting data products are used by several national and international weather centers to improve global weather forecasts since 2006.
NRT-RO was funded by BMBF within the GEOTECHNOLOGIEN research programme 2005-2008. Contact person at GFZ is Dr. Jens Wickert.
GPS on Metop (GRAS)
Metop is Europe's first polar-orbiting satellite dedicated to operational meteorology. It represents the European contribution to a new cooperative venture with the United States providing data that will be used to monitor our climate and improve weather forecasting. The satellite was launched in October 2006.
GPS radio occultation with TanDEM-X
The GPS radio occultation data of the German TanDEM-X-satellite are analysed and globally distributed vertical atmospheric profiles (bending angles, refractivity, temperature, water vapor) are derived and provided for the international user community. TanDEM-X was launched June 21, 2010 and forms together with TerraSAR-X a tandem-satellite configuration.
GPS radio occultation with TerraSAR-X
The GPS radio occultation data of the German TerraSAR-X satellite are analysed and globally distributed vertical atmospheric profiles (bending angles, refractivity, temperature, water vapor) are derived and provided in Near-Real Time for the international user community. The data are used by the internationally leading weather centers to improve their global forecasts.
Overview of GNSS Atmosphere Sounding
During the last decade ground- and space-based GPS (Global Positioning System) techniques for atmospheric sounding came up as a promising tool for global, permanent, weather-independent and calibration-free remote sensing of the Earth's atmosphere and ionosphere with high accuracy. The high expectations of atmospheric scientists all over the world were already satisfied by the demonstration of the GPS potential for various applications in weather forecast, climate research and for atmospheric/ionospheric investigations during the last years.